Comparative Biosciences, Inc. was founded to provide expert resources and quality service to all sectors of the biomedical community.
CBI was founded in 1996 with two scientists and a histology technician in Santa Clara, CA. We have grown each year steadily, increasing and expanding our capabilities and areas of expertise. We feature almost two decades of extensive experience offering GLP and non-GLP preclinical toxicology, efficacy, pharmacology, pharmacokinetics-pharmacodynamics, histopathology, and safety studies on all laboratory species.
We are a fully-staffed, state-of-the-art, AAALAC-accredited purpose-built facility with both an in house histopathology laboratory and a full time quality assurance unit. We are registered with the FDA, USDA, and OLAW and located in the heart of Silicon Valley in Sunnyvale, CA. Our particular areas of expertise include ocular, dermatology, fibrosis, otic/ototoxicity, wound healing, burns, stem cells, oncology, renal, inflammation, immune-mediated, CNS, cardiovascular, infection models, and devices, as well as contract histopathology, immunohistochemistry and custom model development. Our clients range from the smallest virtual company to pharmaceutical giants, academia, defense, and government.
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Immunohistochemistry (IHC) is a key tool in both early research and later stage development. The histology laboratory at CBI is skilled in the histologic preparation of specialized tissues from a range of both common and unusual research and discovery models in both a nonGLP and GLP environment.
-Standard IHC on tissues from all species from fixed and frozen tissues and cytospin preparations
-IHC staining method development, verification, and validation
-In Situ Hybridization and
-Tissue whole mounts with IHC or IF
-Retinal whole mounts
-Tissue Cross Reactivity Studies
-Research cross reactivity
-Histomorphometry and Digital Image Analysis
-Human, primate, and animal tissue bank (fixed and frozen)
-Unusual and rare human tumors and disease tissues
-B-cell lymphoma, lymphoma, lung, ovarian, breast, brain, colon, bladder, melanoma, bone marrow, HLA and other tumors.
CBI can develop or accommodate other specific or modified stains and/or procedures not listed. We are adding new antibodies frequently, so contact us to request an antibody not listed below.
α -2 microglobulin
Glial Fibrillary Acidic Protein (GFAP)
Griffonia simplicifolia Isolectin
Protein Disulfide Isomerase (P4H)
Smooth Muscle Actin (SMA)
Tyrosine Hydroxylase (TH)
Von Willebrand Factor (vWF)
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Comparative Biosciences provides the best quality pre-clinical laboratory services to our clients in the biopharmaceutical and medical device industries on the West Coast and beyond. Our success is achieved through our commitment to customer service, scientific quality, and employee satisfaction. We offer a variety of services in the pre-clinical industry, some listed below:
Pharmacokinetics / pharmacodynamics studies
Stem Cell Research
Thermal Burn Modeling
Heymann Nephritis Model
Oncology Xengraft studies
We offer a complete program of pre-clinical research services to support a range of toxicology. Beginning with early assessment of new molecules including single dose, multiple dose, and targeted studies, as well as directed or investigative toxicology, complete IND enabling toxicology programs, and finishing with long term carcinogenicity studies, CBI provides expertise, attention, and care on every study. Our study directors are experienced, communicative, and attentive, and we produce high-quality GLP reports in a very timely fashion.
CBI provides expertise, attention, and care on toxicology research including early assessment of new molecules with single dose, multiple dose, and targeted studies; directed or investigative toxicology; and complete IND enabling toxicology programs.
Large and small animal toxicology studies. Types of studies include:
CBI offers a robust and validated model of STZ-induced hyperglycemia and retinopathy in rats. Streptozotocin-induced hyperglycemia results in changes in the retinal pigmented layer consisting of increased thickness of the middle retinal layers, increased new vessel formation, reactive endothelium, dilated capillaries distended with either blood or edema fluid, acute inflammation composed of intravascular neutrophils, and neutrophils adhered to vessel walls and extravascularly by 4 weeks or longer post-STZ treatment. These changes were clearly evident histologically and were supported by Optical Coherence Tomography and retinal angiography. Examination of the retina via fluorescein angiographs reveals increases in retinal vascularity in streptozotocin-treated rats with areas of leakage particularly surrounding the optic nerve. These changes were compatible with and correlated with the histopathologic findings of increased vascularity of the retinal pigmented layer. OCT assessments clearly demonstrating thickening of the retina, primarily the middle layers following STZ induction. Treatment with triamcinolone significantly reduced STZ-induced retinal thickness as well as other ocular changes.
CBI has demonstrated expertise in all phases of the drug development process in preclinical contract otic studies-studies relating to the ear. Our highly specialized staff is experienced in providing exploratory/proof-of-concept, GLP toxicology, pharmacokinetics, in vivo animal models, pharmacology, and histopathology/immunohistochemistry associated with the outer, middle and inner ear. Our clients include biopharmaceutical companies, defense and military, government agencies, and medical device companies.
Due to CBI’s unique experience in preclinical contract otic studies and state-of-the-art facilities, we have the skill and expertise to accelerate new ear drugs from discovery through the drug development process to regulatory submission. CBI is committed and dedicated to providing state-of-the-art research and offers a complete range of services to pharmaceutical, biotech, and medical device companies.
We have conducted studies relating new drugs that prevent hearing damage from loud sounds, such as battlefield injury, ear infections, parasitism, chemotherapeutics, antibiotics, acute and chronic tympanic membrane perforations and surgical manipulations. Drug delivery includes systemic, local to the ear canal or tympanic membrane or by infusion into the middle or inner ear. Special techniques include peri-lymph collection, cytocochleograms, hair cell analysis, behavioral analysis, and auditory brainstem response testing (ABR).
We have evaluated many potential anti-cancer compounds in mice and rats. Our in-house expertise allows us to optimally design studies that provide critical preclinical efficacy data. CBI provides a variety of validated cell lines for the assessment of anti-tumor agents. We can help you advance your product by conducting the following evaluations:
CBI offers comprehensive biocompatibility testing, and compliance with ISO-10993, 9394 USP & CFR Compliant Testing in rapid and cost effective manner.
In Vivo Assays
In Vitro Assays
Comparative Biosciences, Inc. has demonstrated expertise in all phases of the drug development process in preclinical contract dermal toxicology studies. Due to our unique and extensive experience in preclinical studies and state-of-the-art facilities, we have the skill and expertise to accelerate new drugs, small molecules, metals, biologics, stem cells, nanoparticles, and devices from discovery through the drug development process, to regulatory submission and studies in man. We offer unique and sophisticated methods of assessment including OCT, laser doppler, ELISA, immunohistochemistry, and Silhouette photography.
Dermal toxicology study expertise at CBI includes:
The histology laboratory at CBI is skilled in the histologic preparation of a large variety of special histochemical stains on FFPE, frozen and plastic embedded tissues from a range of both common and unusual research and discovery models in both a nonGLP and GLP environment. CBI can accommodate other specific or modified stains and/or procedures not listed upon request.
CBI provides contract histology, immunohistochemistry, and pathology services to the biopharmaceutical industry. Whether preparing a single biopsy or a complete carcinogenicity study, CBI offers high quality slide preparation, pathological evaluation, and report preparation in a timely and cost effective manner.
Founded in 1996, CBI is a prestigious, independent, privately owned, nationally and internationally recognized histology and pathology laboratory serving the biopharmaceutical and life sciences industry. We are committed to providing the highest quality histology and pathology services to our clients.
Located in the heart of Silicon Valley, CBI features state-of-the-art laboratories, the most up to date equipment, and an expert staff drawn from the dynamic academic and biotechnology environment surrounding Silicon Valley, Stanford University, UCSF, and Berkeley.
Our resources include highly trained and experienced board-certified veterinary pathologists, skilled and detail-oriented technical personnel, and full-time quality assurance staff. We are committed to providing the highest level of quality in a cost effective and time efficient manner. All CBI studies are conducted within our laboratories, under the direct supervision of our pathologist, QAU, and PhD-level scientific managers.
For preparation of histology and pathology studies for regulatory submission, CBI follows FDA, OECD, EPA, STP, NTP, MHW, FISA, and EMEA guidelines. Our Quality Assurance Unit audits all critical phases of GLP studies and all phases of slide preparation are overseen by a board certified veterinary pathologist assuring the highest quality slide preparation.
Our clients include pharmaceutical and biotechnology companies, universities, colleges of veterinary medicine, NIH/NIEHS/NPT and other federal grant funded organizations, hospitals, and basic researchers.
In situ hybridization (ISH) is a technique used to detect and localize the presence or absence of a specific genetic sequence in tissue using a probe with a complementary polynucleotide sequence. Comparative Biosciences, Inc., offers both fluorescent (FISH) and chromogenic (CISH) in situ hybridization assays. These are available on formalin-fixed, paraffin embedded tissue slides. Dentaturing and hybridization of probes is maintained using automated Dako Hybridizer.
ISH services at Comparative Biosciences, Inc. are flexible to meet your needs.
Comparative Biosciences, Inc. (CBI), a premier ocular toxicology CRO, offers both exploratory proof-of-concept toxicity and tolerability studies, and complete preclinical GLP Toxicology and Safety Assessment Studies suitable for regulatory submission for ophthalmic drugs, biologics, and devices. Ocular toxicity assessments include a range of Acute Tolerability, Sensitization, Range-Finding, Acute, Subchronic and Chronic Toxicology, and special tests of Lacrimation and Pupillary Diameter Testing. CBI offers a complete range of routes of ocular drug administration.
Routes include topical ocular application, and injection routes including intravitreal, subconjunctival, periocular, intracameral, subretinal, intrascleral, transscleral, intrastromal, subtenon, retrobulbar, intracameral, ocular implants or ocular devices.
CBI is versed in ocular toxicology studies employing stem cells, contact lens, punctal plugs, as well as other surgically implanted ocular and intraocular devices.
Specialized techniques including OCT, ERG, tonometry, pachymetry, fundus angiography are available for toxicology and pharmacology assessments.
Species include rodents, rabbits, small animals, dogs, and mini pigs.
Comparative Biosciences, Inc. provides a complete range of research services in the area of pharmacokinetic, toxicokinetic, bioavailability, bioequivalence, and ADME studies.
We feature rapid study initiation and report preparation to meet sponsor deadlines or milestones. We comply with FDA, OECD, and ICH guidelines. Our capabilities in Pharmacokinetics include early exploratory, investigative, or screening studies, cassette dosing studies, juvenile studies, disease model studies, and formal studies that support regulatory submission. We specialize in unusual and customized studies.
Routes of administration
Pharmacokinetic Studies in Disease Models
Disease states can alter the metabolism of some test articles as can treatment with multiple drugs. Consequently, pharmacokinetic assessments in disease models and treatment states may be important. We offer custom pharmacokinetic studies in all the animal models and tumor models that CBI offers.
Large Animal and Colony Studies
CBI maintains a standing colony of healthy dogs, cats, and pigs for use in PK studies for our clients. Alternatively, CBI can also maintain dedicated colonies of dogs, cats or pigs specifically for individual sponsors. Dedicated colonies assure the sponsor that PK studies can be scheduled and conducted very rapidly, usually with a 1-2 week turn around between scheduling and delivery of specimens for analytical assessment.
CBI provides a wide range of established and validated dermal pharmacology and efficacy studies in all species in normal and in diseased animals, and with single, multiple or infusion/slow release dose administration with small molecules, biologics, stem cells, metals, nanoparticles, and devices. CBI also offers custom studies and custom model development. We have sophisticated methods of assessment including OCT, laser doppler imaging, ELISA, immunhistochemistry and Silhouette photography.
In these protocol-driven studies, acute or chronic local dermal inflammation is induced by a variety of means, including for example, administration of mediators or chemoattractants such as fMLP, endotoxin, leukotrienes, cytokines, TNF, or irritants such as turpentine, formalin, or carrageenan, TMA, or intradermal methylated BSA. Test articles are administered and the local anti-inflammatory activity is assessed by various means including wheal size, Draize scores, Miles Assay, histopathology, and immunohistochemistry as per protocol. Rodents, rabbits, and guinea pigs are most suitable for these studies, but minipigs and red duroc swine are also useful. Studies include acute dermal inflammation studies and chronic dermal inflammation studies.
Imiquimod-Induced Murine Model of Psoriasis
Topically applied Imiquimod, an immune modifying toll-like receptor agonist, to susceptible BALB/c mice rapidly induces a psoriatic skin inflammation. There is scaling, erythema and histopathologic lesions similar to human psoriasis.
Dermal Fibrosis (Scleroderma)
In this model of scleroderma or dermal fibrosis, fibrosis is induced by bleomycin administration. Effects of test article on fibrosis formation via clinical signs, histopathology, special stains such as Sirius Red and Trichrome, immunohistochemistry, digital image analysis, and in vitro assays such as Sircol® may be assessed.
The rabbit ear dermal scar model, guinea pig back skin and Red Durocs are well characterized models for scar and keloid formation. Effects of test article on scar formation formation via clinical signs, histopathology, special stains such as Sirius Red and Trichrome, immunohistochemistry, digital image analysis, and in vitro assays such as Sircol® may be assessed.
In this model, a first or second degree burn is induced in rodents or pigs by thermal or UV light methods. Effects of test article on healing and scar formation are assessed. Effects of test article on burn size and healing via clinical signs, bacteriology, histopathology, special stains such as Sirius Red and Trichrome, immunohistochemistry, digital image analysis, and in vitro assays such as Sircol® may be assessed. We offer sophisticated assessments including OCT, laser doppler for blood flow, Silhouette photography and ELISA.
Please view our complete overview of our Thermal Burn Modeling services.
Wound healing studies may be conducted in normal or diabetic (streptozotocin-induced) animals. In these models (pigs, red duroc swine, rabbits, rats), uniform wounds are created surgically and healing assessed. Typical wounds would include full thickness, split thickness, and single cuts. The test article is administered and effects of test article on size, rate and character of healing are determined. Clinical signs, OCT, laser doppler, histopathology, immunohistochemistry, histomorphometry/digital image analysis, and tensile strength are powerful tools in assessment of wound healing.
Dermal Delivery Devices
There are many new experimental methods and devices used to deliver a test article to the skin for either local or systemic absorption. The local or topical effects of these devices on the skin as well as the ability of the device to deliver the test article may be determined thru toxicologic, pharmacologic assessments and especially pharmacokinetic assessments. Dermal delivery devices are important in the delivery of drugs for chronic pain and chronic metabolic diseases; any condition in which slow continuous systemic administration of drugs is needed.
Delayed Type Hypersensitivity Studies
Delayed type hypersensitivity (DTH), sensitization or maximization studies may be employed for two different purposes to determine if:
the test article is a dermal sensitizer itself, or
the test article can suppress an induced delayed type hypersensitivity (DTH) reaction.
CBI offers expertise in the following DTH studies:
Skin sensitization (maximization) study: Beuhler method and Magnusson-Kligman method
Delayed type hypersensitivity study: Oxazolone (TH-2 mediated; back skin or ear thickness)
Delayed type hypersensitivity study: (TH-1 mediated hapten-induced: DNFB, DNCB,TNFB, TNCB, TMA, etc) (back skin or ear thickness)
Intradermal methylated BSA
Murine local lymph node assay for assessment of allergic contact dermatitis potential
Passive cutaneous anaphylaxis
Chemical irritant dermatitis
Dermal Infection Studies
Offers purity, efficacy and safety assessments on Cannabis Products.
Acute Toxicology Studies:
-Maximum tolerated dose
Subacute and Subchronic Toxicology Studies:
-1 week subacute
-2 week subacute
-4 week subchronic
-8 week subchronic
Chronic and Carcinogenicity Toxicology Studies
-3 month chronic
-6 month chronic
-9 month chronic
-1 year carcinogenicity
-2 year carcinogenicity
We offer a complete program of preclinical research services to support a range of toxicology. Beginning with early assessment of new molecules including single dose, multiple dose, and targeted studies, as well as directed or investigative toxicology, complete IND enabling toxicology programs, and finishing with long term carcinogenicity studies, CBI provides expertise, attention, and care on every study. Our study directors are experienced, communicative, and attentive, and we produce high-quality GLP reports in a very timely manner.
"Overall, this was a disappointing experience with Comparative Biosciences. The most surprising thing to me was the complete lack of scientific curiosity on the part of the scientists at this company. It felt like the vendor's chief goals were to churn through the steps of the experiment without regard to the question being asked or the quality of data being delivered. I had asked Comparative Biosciences to conduct a pilot IHC experiment with a new human antibody that were are testing as a therapeutic. As part of the protocol, they agreed to "optimization of staining method for huIgG," then dosing mice and staining tissues for the test material after dosing. After staining, they found that the test material was not found in the mouse tissue and concluded that the test material did not enter the tissue. When asked for controls to demonstrate that their staining method works, they sent a micrograph showing that the secondary antibody they used was able to stain human spleen. Let me repeat: their "optimization" involved staining 1) irrelevant human tissue with 2) only the secondary antibody (without the test material). When asked how they know the secondary antibody binds to my test material, they said that they don't know the epitope of the test material and therefore cannot test it on mouse sections. After a few rounds of back and forth, it was clear they did not understand why staining human tissues with an anti-human secondary antibody was not a good control for IHC in mouse tissues stained with a foreign antigen. I eventually got tired of coaching the scientist and making experimental suggestions."
Comparative Biosciences, Inc. has not received any endorsements.